Shapewear

SKIMS vs Spanx vs Honeylove vs Shapellx vs TheBlackPurple: Which Shapewear Actually Works Best in 2026?

Shapewear

SKIMS vs Spanx vs Honeylove vs Shapellx vs TheBlackPurple: Which Shapewear Actually Works Best in 2026?

by Nima Rafizadeh on Dec 30 2025
Shapewear that looks good is everywhere. Shapewear that helps women over 40 feel good — with lighter legs and less swelling — is rare. This comparison explains the difference so you can choose what matters most to you.
12 Best Compression Leggings for Circulation

Shapewear

12 Best Compression Leggings for Circulation

by Nima Rafizadeh on Dec 23 2025
Discover the best compression leggings for circulation with a side-by-side comparison of 12 top brands. Learn the difference between fashion leggings and true functional compression designed to reduce swelling, support lymphatic flow, and help women over 40 feel lighter and more energized all day.
Best Tummy Control Shapewear Brands for Everyday Wear

Shapewear

Best Tummy Control Shapewear Brands for Everyday Wear

by Nima Rafizadeh on Dec 23 2025
A good shapewear brand doesn’t just smooth — it transforms how you feel in your clothes. According to recent retail data, more than 72% of women over 40 say comfort now matters more than compression when choosing shapewear. That tells us something powerful: control should feel effortless. I’ve spent years testing and reviewing every kind of tummy-control garment imaginable — from high-waist briefs to full-body sculptors — and the difference between a drawer staple and a drawer regret usually comes down to three things: breathability, recovery, and confidence. The best brands don’t just flatten; they support your core, enhance circulation, and move with you, not against you. In this guide, I’ll walk you through the shapewear brands that actually deliver — pieces you can wear all day without feeling squeezed, overheated, or over it. Let’s dive in and find the ones that work with your body, not just on it. TheBlackPurple – Mass & Slim® Collection (Clinically Proven Results) When it comes to shapewear that truly does more, TheBlackPurple’s Mass & Slim® Collection stands in a category of its own. Unlike traditional fashion shapewear that only sculpts, Mass & Slim® is clinically proven to deliver measurable results. Independent laboratory testing confirmed that consistent wear can help reduce inches, smooth cellulite, and improve circulation — real benefits, not marketing promises. What makes this line revolutionary is its Tourmaline bead technology, embedded directly into the fabric. These natural mineral beads gently activate with body heat, creating a subtle micro-massage that stimulates blood and lymphatic flow throughout the day. This improved circulation helps reduce fluid retention and gradually refines your silhouette over time. But here’s what really sets TheBlackPurple apart: it’s not a fashion brand — it’s a functional wellness brand designed to help women feel good. The focus isn’t just on how you look, but on how you feel about the way you look. Each garment lifts, shapes, and supports with a high-waisted, breathable design that adapts to your body rather than squeezing it. You can wear them for 8+ hours a day, even while sleeping or during everyday movement. They’re ideal for women who want discreet, all-day shaping that also promotes better circulation, confidence, and comfort. If shapewear has ever made you feel restricted, Mass & Slim® will make you feel reconnected — to your body, your movement, and your confidence. 👉 Discover the clinically proven Mass & Slim® Collection at TheBlackPurple.com Spanx – The Everyday Icon You can’t talk tummy control without mentioning Spanx. It’s a household name for a reason. Their Higher Power Shorts and OnCore Mid-Thigh Bodysuit are reliable options for everyday smoothing. The material is sleek and compressive, great for layering under fitted clothing. However, some women find Spanx better for shorter wear (a few hours) rather than all-day comfort, as it can feel tight by the afternoon. Still, it’s one of the most consistent performers in the market. Skims – Style Meets Function Kim Kardashian’s Skims line has mastered blending aesthetics with performance. Their Seamless Sculpt Bodysuit offers solid tummy control and a modern, minimalist feel. The fabric is ultra-stretchy and designed to disappear under clothing — great for lighter fabrics or form-fitting outfits. One caveat? The sizing runs snug, so go one size up for comfortable all-day wear. Honeylove – Compression with Structure If you prefer shapewear that feels firm and supportive, Honeylove is worth exploring. The SuperPower Short uses targeted compression panels to contour the waist and lower tummy while staying breathable. It’s an excellent choice if you like a more “held-in” feeling — especially for special occasions or long workdays. Yummie – Everyday Ease For those who prefer light to medium compression, Yummie offers a practical option. Their Tanya Shaping Tank and Rachel Leggings deliver gentle tummy control and are easy to wear under daily outfits or activewear. They don’t sculpt as deeply as others on this list, but the comfort factor is high — and sometimes, that’s what matters most. Final Thoughts At the end of the day, the best tummy-control shapewear is the one you can actually live in. That’s where TheBlackPurple’s Mass & Slim® Collection stands out. It doesn’t just sculpt your silhouette; it helps reduce inches, improve circulation, and smooth the skin — all backed by clinically proven results. The difference is that Mass & Slim® isn’t about changing your body — it’s about feeling good in your body. If you’re tired of shapewear that feels like armor, it’s time to choose something that works with your body, not against it. 👉 Explore the full Mass & Slim® Collection at TheBlackPurple.com — and rediscover what comfortable control truly feels like.
Best Anti-Cellulite Shapewear in 2025: Real Results, Science, and Customer Stories

Shapewear

Best Anti-Cellulite Shapewear in 2025: Real Results, Science, and Customer Stories

by Nima Rafizadeh on Dec 23 2025
Can Shapewear Really Help Hide or Reduce Cellulite? Cellulite is normal—over 85% of women see it, regardless of age or fitness. But in 2025, shapewear does a lot more than just smooth bumps. Today's most advanced anti-cellulite shapewear uses compression, circulation-boosting fabrics, and micro-massage tech (like Tourmaline beads) to visibly minimize dimples and energize your legs. See how Mass & Slim Shapewear Shorts look on real bodies: "I love my BlackPurple!! I have been wearing mine for about a month and I definitely can see a difference in cellulite on the back of my legs. They also help keep my thighs from rubbing together in my workout clothes. They give me a slimming look and feel great every day!!" — Teresa Pulido, MO, USA "After only a week, my skin is smoother and there has been a significant change. I wear them to bed only. Looking forward to continued use." — Natalue Angelman, USA "I truly love The Black Purple shorts. I've went from a size 18 to a 14. If any ladies want to try it out, you will see a difference. I saw visible changes after 28 days." — Adean Vinson, USA Does Shapewear Cover Cellulite? Yes—high-quality shapewear like Mass & Slim smooths your silhouette instantly under clothes. Unique to Mass & Slim, the inner Tourmaline beads gently massage your skin and boost circulation as you move, helping fade the look of cellulite with consistent wear. Does Anti-Cellulite Shapewear Actually Work? Shapewear that combines compression and micro-massage isn’t just hype—many women report firmer, smoother skin after a month. It works best when worn 8+ hours a day, especially during activity. "I have worn other brands of these types of pants but none compare to the way these make my body look and feel. Definitely buying another pair!" — Natasha Brown, USA "I was skeptical, but I gave it a try. TheBlackPurple is real. I'm doing the 30-day challenge and will need a new pair because of the inches I have lost in just the first week and a half. If you are on the fence ... just do it." — Neeshenah Porter, USA What’s the Most Effective Anti-Cellulite Shapewear? Mass & Slim Shapewear Shorts—Clinically inspired Tourmaline beads, proven compression, sizes XS-3XL, 60-day guarantee Other leading brands—Standard compression only, limited results for stubborn cellulite What sets Mass & Slim apart? Customer results, comfort, and real improvement: "My skin looks & feels smoother, and I look smaller and “tighter” overall in my hips, thighs, butt, and stomach. Bonus: they act like shapewear, so I look better in my clothes too!" — C Westphal, USA Do Compression Leggings or Shorts Really Help with Cellulite? Yes! Compression increases circulation and can help flush excess fluids—key to smoothing skin over time. The Mass & Slim Leggings and Shorts are designed for 8+ hours of comfortable daily wear, even under scrubs or jeans. "I'm a nurse, these are amazing under my scrubs. It's like a booty massage for my 10 hour shifts. Keeps my lumpy thighs looking tight." — Cyndee LaVonne, USA   Mass & Slim Shapewear Shorts $79.95 $99.95   Shop Now Mass & Slim Shapewear Leggings $89.95 $104.95   Shop Now Popular Cellulite Questions Answered Does shapewear hide cellulite? Yes, instantly under clothes, and can visibly reduce it with time. How do celebrities hide cellulite? Many use medical treatments, but shapewear is a common red-carpet trick! For non-surgical results, consistent wear matters most. Should you wear shapewear while losing weight? Absolutely—it boosts confidence and helps prevent chafing and sagging skin as you lose inches. Does anything actually work to get rid of cellulite? No single solution erases cellulite, but combining shapewear, hydration, activity, and massage gives real, visible improvements. Expert Tips for Best Results Wear Mass & Slim Shorts or Leggings 8+ hours a day for 30 days Rotate pairs for daily freshness Combine with hydration and gentle dry brushing for faster results Follow our sizing guide for your perfect fit Mass & Slim Reviews: Real Women, Real Results   "They hold everything in. I wear them to bed and they even help with my back problems. Need extra pair so I can always wear them. Get them you won’t be disappointed!" — Joan Zupo, FL, USA "I have only had these for about a week. I love the support I feel while wearing them but they aren't restrictive. I can still move and breathe. They also make my clothes feel like they fit better and look better. I can't wait to see results in a few more weeks!" — Tammy King, USA "I absolutely love the Mass & Slim shorts! They are very thin but have amazing compression. Can't even tell I am wearing them underneath tight skinny jeans. These shorts work!" — Joan Langdon, USA   Quick FAQ Does shapewear cover cellulite? Yes, quality shapewear like Mass & Slim smooths and covers cellulite under clothes, with added long-term skin benefits. Does anti-cellulite shapewear actually work? Yes! Consistent daily wear helps reduce the look of cellulite for most women, especially with compression and massage technology. Do compression leggings help with cellulite? Yes, they boost circulation and smooth skin—especially when worn daily for 8+ hours. Mass & Slim leggings are a top-rated choice. Which anti-cellulite treatment is most effective? Professional treatments are costly, but for non-surgical options, shapewear with massage beads and consistent compression offers visible, affordable results. The Bottom Line: Confidence, Comfort, Results You don’t need to be a celebrity or spend thousands to feel better in your skin. Mass & Slim Shapewear gives you visible results, proven comfort, and real support—no surgery, no downtime. Shop now and get $20 off two or more!
Lipedema vs. Cellulite

Shapewear

Lipedema vs. Cellulite

by Nima Rafizadeh on Dec 23 2025
Understand the difference between lipedema and cellulite, and discover effective lifestyle and treatment approaches for smoother, healthier legs.
How Compression Shapewear Can Help Alleviate Lymphedema Symptoms

Shapewear

How Compression Shapewear Can Help Alleviate Lymphedema Symptoms

by Nima Rafizadeh on Dec 23 2025
Learn how compression shapewear supports lymphatic flow, reduces swelling, and provides everyday comfort for those managing lymphedema.
Can You Sleep In Compression Wear? - TheBlackPurple

Shapewear

Can You Sleep In Compression Wear?

by Nima Rafizadeh on Dec 23 2025
Wondering if you can wear compression garments to bed? We break down the safety, benefits, and comfort tips so you can decide what’s right for you.
QWO Cellulite Treatment: Why Was It Discontinued?

Shapewear

QWO Cellulite Treatment: Why Was It Discontinued?

by Nima Rafizadeh on Dec 23 2025
QWO cellulite treatment is gone—but cellulite solutions remain. Discover why it was discontinued and how Mass & Slim shapewear offers a safer, proven alternative.
The Appearance of Cellulite Worsening in the Summer Sun | The Black Purple

Shapewear

3 Ways the Summer Sun Can Worsen the Appearance of Cellulite

by Nima Rafizadeh on Dec 23 2025
You’ve been waiting all winter to get outside to enjoy the warm summer sun and we have to ruin it by telling you the sun can ruin the appearance of your cellulite. First, it’s not all bad news. You can easily enjoy being outside in summer without worrying about the sun making your cellulite look worse. Mass & Slim Shapewear Shorts $79.95 $99.95 Shop Now Mass & Slim Shapewear Leggings $89.95 $104.95 Shop Now How the Sun Affects Your Cellulite Well, it’s not really the sun itself, but the harmful UV rays in sunshine. And we can all tolerate some sun exposure without any ill effects, but that can be just a few minutes some days if you don’t use sun protection. Over-exposure to the sun’s UV rays can harm your skin in the following ways that can make your cellulite appear worse than normal 1.Damages Collagen Collagen is the most abundant protein in your body. Like all proteins, it promotes cell growth, particularly in the connective tissue throughout your body, including in your bones, muscles, tendons and skin.Collagen makes your skin stronger and more elastic. UV Rays can damage the collagen in your skin, which weakens the skin and makes it more susceptible to the puckering of cellulite 2.Causes Uneven Thickening of the Skin UV rays can cause solar elastosis, which is an uneven thickening of the skin due to overexposure to the sun. The thickened skin can appear yellow and bumpy. Even if you didn’t have cellulite, solar elastosis would make it look like you did. 3.Robs the Skin of Moisture The sun dries the skin in a way that causes it to wrinkle and crack. Even worse, it robs the skin of the moisture that keeps the skin elastic and strong, so it can make your cellulite dimples look deeper. You might need to do more than usual to keep your skin healthy and your cellulite minimized during the summer. Wearing anti-cellulite Mass & Slim shapewear that’s clinically proven to reduce inches and the appearance of cellulite can help. Active Slim Compression Leggings $99.95 $129.95 Best Seller! Shop Now Secret Slim Compression Shorts $94.95 129.95 Best Seller! Shop Now Reviews I am a critical care nurse and these leggings are saving my legs. I am no longer feeling leg fatigue at the end of my shift which has alleviated my knee pain. In addition my legs look smoother. My husband noticed the back of my thighs appeared less dimpled and he was a skeptic. I am ordering a second pair and I am going to try the bra this time too. Leann Kolovitz, USA. I have been wearing my mass and slim leggings for less than a week. I have already noticed tightening and toning in my legs, butt and stomach. I`m also seeing a reduction in cellulite and smoothing of my skin. Very impressed for the first week! I never submit reviews but if you are looking for something to help get u in shape and to look toned, these leggings are the bomb! Worth every dime I paid. I will post back in thirty days with an update but so far I`m extremely thrilled with these leggings! Great results! Pam Crawford, USA. See All Reviews
Kim Kardashian Takes One Step Forward & Two Steps Back on Cellulite - TheBlackPurple

Shapewear

Kim Kardashian Takes One Step Forward & Two Steps Back on Cellulite

by Nima Rafizadeh on Dec 23 2025
Kim Kardashian embraces her body—cellulite and all. Here’s her perspective, plus simple ways to feel confident in your own skin.
Cellulaze Q&A: Costs, Real Results, Long-Term Benefits & Alternatives

Shapewear

Cellulaze Q&A: Costs, Real Results, Long-Term Benefits & Alternatives

by Nima Rafizadeh on Dec 23 2025
Discover the real facts about Cellulaze for cellulite—cost, results, recovery, and the best non-surgical alternatives for smoother skin.
Nurse wearing Mass & Slim anti-cellulite leggings under scrubs for circulation and cellulite support.

Shapewear

Do Anti-Cellulite Leggings Really Work? The Truth Behind the Hype

by Nima Rafizadeh on Dec 23 2025
Anti-cellulite leggings promise smoother legs and better circulation. Here’s the truth on how they work, their benefits, and real-life results.
Woman taking a mirror selfie in underwear with visible cellulite, standing confidently in front of a closet. Text overlay reads "CELLULITE AND YET, I STILL LOVE MYSELF" with a pink heart.

Shapewear

Cellulite Q&A: What Works, Real Results & Mass & Slim Shapewear Reviews

by Nima Rafizadeh on Jul 29 2025
Watch real customers answer top cellulite questions and share honest reviews of Mass & Slim shapewear. Learn what really works for cellulite, from diet to compression.
Understanding Lipedema

Shapewear

Understanding Lipedema

by Nima Rafizadeh on Jul 25 2025
Lipedema is more than just stubborn fat—it’s a progressive condition affecting millions of women. Discover how compression leggings with massaging Tourmaline beads can ease symptoms, improve circulation, and help you feel better every day.
Cellulite After 45: Causes, Myths & How to Reduce It for Smoother Skin

Shapewear

Cellulite After 45: Causes, Myths & How to Reduce It for Smoother Skin

by Nima Rafizadeh on Jul 15 2025
What Exactly is Cellulite, and How Does it Develop? Cellulite is a common, harmless skin condition characterized by dimpled skin, often appearing on thighs, hips, buttocks, and abdomen. It develops when fat cells push against connective tissue beneath the skin. Is it Actually Possible to Get Rid of Cellulite Completely? Completely eliminating cellulite is challenging, but its appearance can significantly improve with various treatments and lifestyle adjustments. At What Age Do Women Typically Start Noticing Cellulite? Women typically notice cellulite post-puberty, with increased visibility often around menopause due to hormonal and skin elasticity changes. Does Cellulite Disappear with Weight Loss or Exercise? While weight loss and exercise can reduce cellulite's appearance by reducing underlying fat, they generally do not completely eliminate it. Is Having Cellulite Unhealthy or Harmful? No, cellulite is purely cosmetic and does not pose any health risks. Effective Methods for Reducing the Appearance of Cellulite Lifestyle Changes: Diet and Exercise A balanced diet and regular physical activity can significantly diminish cellulite appearance by improving circulation and reducing fat deposits. Effectiveness of Creams, Lotions, and Topical Treatments Topical creams containing caffeine or retinol can temporarily improve cellulite appearance by tightening skin and stimulating collagen production. Professional Treatments: Acoustic Wave Therapy, Laser Treatment, Radiofrequency, and Subcision These clinical treatments provide longer-lasting improvements by targeting underlying fat and connective tissue structures. Popular Trends: Dry Brushing, Cupping, and Herbal Remedies These methods might temporarily improve skin texture through enhanced circulation, though evidence of long-term effectiveness remains limited. How Do Models or Public Figures Manage Cellulite Visibility? Public figures often utilize professional treatments, strategic clothing choices, makeup, lighting techniques, and photo editing to manage cellulite visibility. Do Men Typically Notice Cellulite? Generally, cellulite is far less noticeable to others, including men, than women perceive. Role of Hormones and Genetics in Cellulite Appearance Hormones like estrogen and genetic predisposition significantly influence cellulite development and visibility. How Does Cellulite Differ from Medical Conditions like Lipedema? Unlike cellulite, lipedema is a medical condition characterized by painful fat accumulation and swelling, requiring medical treatment. Can Specific Dietary Choices or Supplements Help Manage Cellulite? A nutrient-rich diet and supplements promoting circulation, such as grape seed extract and ginkgo biloba, may support skin health and reduce cellulite. Preventive Measures to Reduce Cellulite Risk Maintaining a stable weight, staying hydrated, regular exercise, and skincare routines can prevent or lessen cellulite severity. Embrace Your Body: Supportive Solutions for Confidence Embrace body positivity and enhance confidence using supportive solutions such as Mass & Slim Anti-Cellulite Shorts, designed specifically for women over 45 to improve circulation and reduce cellulite appearance. For more resources and products, visit TheBlackPurple.com. References: Mayo Clinic, Cleveland Clinic, Healthline, Wikipedia
Regular Leggings vs. Compression Leggings:

Shapewear

Regular Leggings vs. Compression Leggings:

by Nima Rafizadeh on Jul 11 2025
What Nurses and Women Over 45 Should Know "I’ve never had a pair of leggings make my legs feel lighter—until now."—Brandi Lacey, RN, Age 47 If you’re a nurse on your feet all day or a woman over 45 struggling with swelling, aching legs, or cellulite that just won’t budge, your leggings might be working against you. Most regular leggings? They're stretchy but do little for your circulation. They might smooth—but they don’t sculpt. And by the end of a long shift or a busy day, your legs feel just as heavy as they did that morning—if not worse. That’s where compression leggings with Tourmaline bead technology change the game. At TheBlackPurple.com, we’ve seen women—especially nurses—swap their go‑to leggings for our Mass & Slim Compression Leggings Black, and the results have been nothing short of transformative. Backed by science and customer stories, these leggings are more than just shapewear—they’re wellness wear. What’s Hiding in Your Regular Leggings? Regular leggings are often made with low-quality synthetic blends that may feel soft—but offer no support for your legs, circulation, or skin health. In many fast-fashion versions (like those sold on Amazon), you don’t even know what the fabric is. It could include microplastics, chemical dyes, or undisclosed materials that press against your skin all day—especially while sweating or moving. Your skin is your body’s largest organ. Do you really want mystery fabric touching it daily? Yes, regular leggings are cheap and stretchy—but they’re not made for long-term shaping, comfort, or wellness. They often lose shape, bunch at the knees, and provide zero support for blood flow or fluid retention—key concerns for nurses and women over 45. What Makes Compression Leggings Different? Compression leggings are designed to apply strategic pressure to help improve blood flow, reduce swelling, and support your muscles. Our Mass & Slim Compression Leggings Black go beyond typical compression by incorporating Tourmaline beads into the fabric, which create a micro-massaging effect that stimulates circulation and lymphatic drainage. Benefits Our Customers Report: Reduced swelling after just a few wears Smoother-looking legs over time Less leg fatigue after long shifts Lifted silhouette and better support under or over clothes This isn’t just another pair of leggings. These are nurse-approved compression leggings and anti-cellulite shapewear designed for comfort, science-backed support, and real results. Real Results from Real Nurses Brandi, a nurse from Pennsylvania, told us: "After 12-hour shifts, my legs used to feel like bricks. The Mass & Slim leggings actually helped with circulation. I feel less tired and more supported—plus they lift my butt!" Kim, a 52-year-old caregiver, added: "These are the only leggings I’ve worn that I can comfortably sleep in. The compression is strong but not suffocating. I even wore them post-surgery for swelling." Watch how nurses feel after wearing Mass & Slim Compression Leggings. Why Compression Matters After 45 As we age, our circulation and lymph flow slow down. This can lead to swelling, puffiness, varicose veins, and stubborn cellulite. Compression wear can help prevent fluid buildup, reduce inflammation, and sculpt your overall silhouette. Combined with the Tourmaline massaging technology, our leggings go beyond appearance—they deliver functional wellness support from the inside out. Shapewear vs. Compression: When to Wear Each Mass & Slim Shapewear (Gray) Worn discreetly under clothing Soft, breathable, and flexible Ideal for daily shaping and smoothing Mass & Slim Compression Leggings Black Worn as outerwear Offers firmer compression Perfect for nurses, long shifts, workouts, swelling, and travel Both options improve circulation and reduce inches and cellulite over time. If you're new to compression, consider sizing up in the black version for extra comfort. Final Thoughts If you’ve ever asked yourself, “Why do my legs feel so heavy after doing nothing?”—the answer might be your leggings. Choosing compression leggings like Mass & Slim Black may be one of the best steps you take for your legs, comfort, and confidence. And if you're a nurse? They're made with you in mind. Explore our full compression collection: Shop now at TheBlackPurple.comUse code TWOORMORE for $20 off 2 or more.
Why Your Legs Swell After 40, And What You Can Do About It Naturally

Shapewear

Why Your Legs Swell After 40, And What You Can Do About It Naturally

by Nima Rafizadeh on Jul 08 2025
This blog explores the real causes of swelling in women over 40—from hormones and poor circulation to lymphedema—and offers natural ways to find relief. Discover how targeted compression wear with Tourmaline beads can ease discomfort, improve circulation, and fit seamlessly into your daily routine. Featuring real testimonials and actionable wellness tips, this guide is a must-read for anyone ready to feel lighter, energized, and supported—naturally.
"Four nurses in hospital uniforms smiling and holding Mass & Slim compression leggings by TheBlackPurple, showcasing support for wellness and circulation during long shifts.

Shapewear

Why Nurses, Moms & Women Over 45 Swear by These Compression Leggings and Anti-Cellulite Shapewear

by Nima Rafizadeh on Jul 04 2025
Discover why nurses, moms, and women over 45 are raving about Mass & Slim®—short for Massage and Slimming. These smart compression leggings and anti-cellulite shapewear improve circulation, reduce inches, and deliver real results with all-day comfort.
What Is PoTS? Symptoms, Causes & Relief for Women

Shapewear

What Is PoTS? Symptoms, Causes & Relief for Women

by Nima Rafizadeh on Jul 01 2025
POTS affects millions—mostly women. Learn how symptoms like fatigue, dizziness, and bloating can be managed with real solutions, including compression wear
Does Anti-Cellulite Shapewear Really Work?

Shapewear

Does Anti-Cellulite Shapewear Really Work?

by Nima Rafizadeh on Jun 27 2025
Real women 45+ are seeing smoother skin and fewer inches with anti-cellulite shapewear. See what’s actually working—and why Mass & Slim is going viral.