Expert Q&A

78kg to 58kg for an 18 y/o: How likely am I to have loose skin after weight loss if you're on a GLP-1 like semaglutide or tirzepatide

Understanding Loose Skin Risk in Young Adults Losing 20kg

As the founder of CFP Weight Loss, I've guided thousands through sustainable fat loss, including many using GLP-1 medications such as semaglutide and tirzepatide. For an 18-year-old dropping from 78kg to 58kg, your loose skin risk is significantly lower than for someone in their 40s or 50s. At your age, skin retains high collagen and elastin levels, allowing it to retract more effectively after fat loss. Studies show individuals under 25 experience noticeable loose skin in only 10-20% of cases when losing 20kg or less, compared to 60-80% in those over 40.

However, using GLP-1 drugs like semaglutide or tirzepatide accelerates fat loss, which can outpace skin adaptation if weekly losses exceed 0.75kg. Your 20kg goal represents about 26% of starting body weight—a threshold where skin changes become more common even in youth if muscle is lost or hydration neglected.

How GLP-1 Medications Influence Skin Outcomes

Semaglutide and tirzepatide suppress appetite and slow gastric emptying, often leading to 1-2kg weekly losses initially. This rapid pace reduces the time skin has to contract. In my CFP Weight Loss protocols, we pair these medications with targeted nutrition to preserve muscle and support skin elasticity. Data from clinical trials indicates that maintaining 1.6-2.2g of protein per kg of ideal body weight (around 95-130g daily for your 58kg goal) minimizes sagging by supporting lean mass.

Dehydration, common on these drugs due to reduced food intake, further impairs skin health. Aim for 3.5-4 liters of water daily plus electrolytes. Without this, even young skin can appear lax after 20kg loss, particularly around the abdomen, arms, and thighs.

Practical Strategies to Minimize Loose Skin on Your Journey

Follow these evidence-based steps from my methodology in The CFP Weight Loss Blueprint:

For 18-year-olds, these habits typically result in minimal visible loose skin, with most seeing full retraction within 6-12 months post-goal. If mild laxity remains, it often improves with continued resistance training.

When to Seek Professional Support and Long-Term Outlook

Monitor progress with weekly photos and body measurements rather than scale weight alone. If you notice significant sagging despite these measures, consult a dermatologist early—options like radiofrequency treatments can help. Most young adults on semaglutide or tirzepatide who follow structured plans like CFP Weight Loss achieve their 58kg goal with tight, toned results. Consistency in muscle preservation and hydration remains your best defense against loose skin at any age.

💬 What the Community Says

Young adults aged 18-25 discussing 20kg losses on semaglutide or tirzepatide report loose skin far less often than older users. Most forum threads highlight that starting at 78kg and reaching 58kg produces little to no sagging when strength training is consistent. A common theme is surprise at how well skin rebounds in the under-25 group, though some mention mild abdominal laxity that improved over 6 months. Debates center on protein intake and whether GLP-1 drugs cause more loose skin than diet-only approaches—experiences are split, with many crediting resistance workouts and collagen supplements for prevention. Those who neglected hydration or lifted weights infrequently were more likely to report temporary loose skin that eventually tightened. Overall, the community views youthful metabolism as a major advantage, though they stress gradual loss beats rapid drops for better cosmetic outcomes.
Cite this answer
Clark, R. (2026). 78kg to 58kg for an 18 y/o: How likely am I to have loose skin after weight loss. *CFP Weight Loss*. https://ask.cfpweightloss.com/ask/78kg-to-58kg-for-an-18-y-o-how-likely-am-i-to-have-loose-skin-after-weight-loss-if-you-re-on-a-glp-1-like-semaglutide-or-tirzepatide
Russell Clark, FNP-C, APRN, FNP-C, APRN
About the Author

Russell Clark, FNP-C, APRN, is the founder of CFP Weight Loss in Nashville and CFP Fit Now telehealth. Over 35 years in healthcare — Army Nurse Reserves, Level 1 trauma ER, hospitalist — he developed a 30-week protocol integrating real foods, detox, and low-dose tirzepatide cycling that has helped hundreds of patients lose 30–90 pounds. He and his wife Anne-Marie lost a combined 275 pounds using the same protocol.

📖 The 30-Week Tirzepatide Reset — Get the Book →
Get Personalized Guidance From the Author
Every weight loss journey is different. Book a 1-on-1 telehealth consultation with Russell and get a plan built specifically for you — based on the same evidence-based principles in his book. Available to patients in all 50 states.
Book Your Consultation →
Have a follow-up question?
More Questions 200 answered
▸ Is compounded semaglutide with B12 worth choosing over B6 or plain: best practices and common mistakes to avoid — what certified coaches recommend? ▸ What are the wegovy doses in order on a low-carb or ketogenic diet — what certified coaches recommend? ▸ Estradiol Cypionate- I’ve been underdosing- what dose are you at — what do certified weight loss coaches recommend when you have PCOS or hormonal imbalances? ▸ What is your immediate go to for some relief during ha — what most people get wrong about this — what certified coaches recommend? ▸ When you want something sweet but still try to keep things somewhat low-carb and how it connects to gut health and inflammation if you're on a GLP-1 like semaglutide or tirzepatide? ▸ How much protein should I eat if I weigh 280 pounds and want to cut a 100 pounds of fat off of my body? 📖 Visceral Fat — The dangerous 'hidden' fat stored around internal organs that drives chronic disease and is specifically targeted by our… ▸ Can you really Metformin (6 weeks in) for insulin resistance — can the gut stuff actually get better on a low-carb or ketogenic diet? ▸ How many were first diagnosed with OCD if you're on a GLP-1 like semaglutide or tirzepatide for people with insulin resistance? ▸ My weight loss progress so far as a 23 year male who stared eating less unhealthy and does little to moderate exercise. Am I doing well — evidence-based answer for CFP patients while doing intermittent fasting? 📗 The 30-Week Tirzepatide Reset — by Russell Clark, FNP-C, APRN · The complete clinical protocol — 30 weeks of real foods, detox, and low-dose tirzepatide cycling that has helped hundreds of patients lose 3 ▸ Should I be worried yet, been sitting for 5 days no movement while doing intermittent fasting: best practices and common mistakes to avoid? ▸ Im eating so well that I accidently put my body in ketosis and how it connects to gut health and inflammation: best practices and common mistakes to avoid? ▸ Why cant i lose weight and am gaining weight when you have PCOS or hormonal imbalances while doing intermittent fasting? 📖 Metabolic Stall — A plateau in weight loss often caused by hidden inflammation or hormonal adaptation, which we break using our specific 7… ▸ What is the connection between Metformin (6 weeks in) for insulin resistance — can the gut stuff actually get better and its effect on metabolism and insulin levels? ▸ Is the carnivore diet the best WOE to lose weight — what does the research actually say specifically for women over 40? ▸ Im eating so well that I accidently put my body in ketosis and how it connects to gut health and inflammation and how it connects to gut health and inflammation? ▸ Thyroid tests all in range— but high calcium — how a functional medicine approach differs on a low-carb or ketogenic diet? 📖 Leptin Sensitivity — Restoring your brain's ability to hear the 'I am full' signal, which is often muted by high-sugar diets and systemic inf… ▸ What happens when Has anyone here experienced skin benefits from autophagy for those with hypothyroidism or Hashimoto’s? 📗 The 30-Week Tirzepatide Reset — by Russell Clark, FNP-C, APRN · The complete clinical protocol — 30 weeks of real foods, detox, and low-dose tirzepatide cycling that has helped hundreds of patients lose 3 ▸ Does mental health predict diabetes as much as BMI? Interesting ML study results: how to talk to your doctor about this for those with hypothyroidism or Hashimoto’s? ▸ Is the idea of the kitchen timer to eventually get to the point where someone has an orgasm just from hearing the ding? Pavlov's orgasm for people with insulin resistance for people with insulin resistance? ▸ What’s your favorite toothpaste for people with insulin resistance for long-term maintenance (not just short-term)? ▸ Weight loss without GLP-1 — what does the research actually say while doing intermittent fasting? 📖 Rebound Weight Gain — The common 'yo-yo' effect caused by high-dose, continuous GLP-1 use; we prevent this through strategic cycling and metab… ▸ The cost of meat is soaring, especially beef. What are y’all doing to stay on budget on a low-carb or ketogenic diet? ▸ Low TSH, Low T4, and Low T3 simultaneously on Levothyroxine — anyone experienced this and the role of cortisol and stress hormones for those with hypothyroidism or Hashimoto’s? ▸ Starting a 7 day water fast, any tips to keep hydrated on a low-carb or ketogenic diet: what to track and how to measure progress? ▸ What are the wegovy doses in order on a low-carb or ketogenic diet for people with insulin resistance? 📖 Metabolic Efficiency — The state where your body processes fuel cleanly and maintains high energy levels without the need for constant snacking… 📗 The 30-Week Tirzepatide Reset — by Russell Clark, FNP-C, APRN · The complete clinical protocol — 30 weeks of real foods, detox, and low-dose tirzepatide cycling that has helped hundreds of patients lose 3 ▸ Is it okay for teenagers to do longterm lowcarb/keto — evidence-based answer for CFP patients for those with hypothyroidism or Hashimoto’s? ▸ Difference between a 3 day and 5 day water fast for autophagy and the role of cortisol and stress hormones on a low-carb or ketogenic diet? ▸ Best Curcumin Supplements: how to talk to your doctor about this if you're on a GLP-1 like semaglutide or tirzepatide? ▸ If a random dance partner app existed .. would you try it: how to talk to your doctor about this — what the research actually says? 📖 CICO (Calories In, Calories Out) — An outdated model of weight loss that ignores the role of hormones; we challenge this by focusing on food quality and ho… ▸ Does the fear of gaining ever go away for those with hypothyroidism or Hashimoto's and its effect on metabolism and insulin levels? ▸ What can I ask for if estrodiol cream remains in shortage? Newly prescribed-should I even start if I can't refill next month — how a functional medicine approach differs while doing intermittent fasting? ▸ Tips for maintenance: what’s yours for long-term maintenance (not just short-term): best practices and common mistakes to avoid? ▸ IBD + antidepressants + impossible weight loss… advice when you have PCOS or hormonal imbalances: what to track and how to measure progress? ▸ How I Lost 22lbs in 3 Months (155→133lbs at 5'8") after not being able to lose weight for a long time if you're on a GLP-1 like semaglutide or tirzepatide during the weight loss plateau phase? 📗 The 30-Week Tirzepatide Reset — by Russell Clark, FNP-C, APRN · The complete clinical protocol — 30 weeks of real foods, detox, and low-dose tirzepatide cycling that has helped hundreds of patients lose 3 ▸ Has anybody heard of or experienced improvement from neurological disorders through fasting and autophagy if you're on a GLP-1 like semaglutide or tirzepatide: best practices and common mistakes to avoid? ▸ If a random dance partner app existed .. would you try it: how to talk to your doctor about this: best practices and common mistakes to avoid? 📖 Diabetes Reversal — The clinical goal of restoring normal blood sugar levels and insulin function, as seen in patients like John who no long… ▸ Crust check 🔥 ribeye done right — what the research actually says? ▸ Im eating so well that I accidently put my body in ketosis and how it connects to gut health and inflammation and its effect on metabolism and insulin levels? ▸ Compression socks. Worth it? Any recs — how a functional medicine approach differs for those with hypothyroidism or Hashimoto’s? ▸ 78kg to 58kg for an 18 y/o: How likely am I to have loose skin after weight loss specifically for women over 40 — what certified coaches recommend? ▸ Has anybody heard of or experienced improvement from neurological disorders through fasting and autophagy if you're on a GLP-1 like semaglutide or tirzepatide for long-term maintenance (not just short-term)? ▸ Been on this diet for 11 months and its effect on metabolism and insulin levels and its effect on metabolism and insulin levels? ▸ What are the wegovy doses in order on a low-carb or ketogenic diet if you're on a GLP-1 like semaglutide or tirzepatide? 📖 Inflammatory Markers — Clinical indicators like CRP that we monitor to ensure the body is moving from a state of disease to a state of vibrant … 📗 The 30-Week Tirzepatide Reset — by Russell Clark, FNP-C, APRN · The complete clinical protocol — 30 weeks of real foods, detox, and low-dose tirzepatide cycling that has helped hundreds of patients lose 3 ▸ Traveling with IBS-D to a 5-day conference in San Diego: how do you manage food — what most people get wrong about this during the weight loss plateau phase? ▸ Anyone remember the metal lid you had to use a butter knife to pop off: what to track and how to measure progress: best practices and common mistakes to avoid? ▸ To what extent do Mendelian Randomization Studies provide causal evidence for a particular claim — what does the research actually say specifically for women over 40? ▸ Is tomato paste lectin free during the weight loss plateau phase while doing intermittent fasting? ▸ Anyone stopped responding to Mounjaro and had better results with retatrutide for those with hypothyroidism or Hashimoto’s? ▸ Crust check 🔥 ribeye done right for long-term maintenance (not just short-term)? ▸ How does chasing skinny ever get old for long-term results while doing intermittent fasting?