Testosterone + Diet: More Fat Loss, Less Muscle Loss

Dieting men on placebo lost fat AND muscle; men on testosterone lost almost only fat.

This article walks through the BMC Med (2016) paper in plain English: what was studied, what changed, what the limits are, and what it does not prove. Full citation and DOI link are at the end, with a PubMed record.

What the study found

Researchers in Australia randomized 100 obese men with total testosterone at or below 12 nmol/L to testosterone undecanoate injections or placebo for 56 weeks. Every man did a 10-week very-low-energy diet followed by 46 weeks of weight maintenance. Body composition was measured by DXA and visceral fat by CT.

Compared with placebo, the testosterone group lost 2.9 kg more fat mass and more visceral fat, and ended with 3.4 kg more lean mass. The authors concluded weight loss on testosterone was almost exclusively fat. It was a single-center trial with 82 completers.

Key finding (from the study record): Fat mass -2.9 kg more vs placebo (P=.04), visceral fat greater reduction; lean mass loss attenuated by 3.4 kg (P=.002) - weight loss on T was 'almost exclusively' fat.

How the study was done

• Design: Randomised double-blind placebo-controlled trial
• Who was studied: 100 obese men, T <=12 nmol/L, very-low-energy diet then maintenance, 56 weeks
• Journal / year: BMC Med (2016)
• First author: Ng Tang Fui M et al.

From the abstract: BACKGROUND: Whether testosterone treatment has benefits on body composition over and above caloric restriction in men is unknown. We hypothesised that testosterone treatment augments diet-induced loss of fat mass and prevents loss of muscle mass. METHODS: We conducted a randomised double-blind, parallel, placebo controlled trial at a tertiary referral centre.

What it means — and what it does not

Useful takeaway: Dieting men on placebo lost fat AND muscle; men on testosterone lost almost only fat.

Limits and caveats: Single center, 82 completers. Intramuscular testosterone undecanoate. Obese men with low-normal T.

This evidence can inform a conversation with a licensed provider. It is not a guarantee of similar results for you, and it is not a recommendation to start, stop, or change any medication on your own.

Related research we cite

• THERAPY OF ENDOCRINE DISEASE: Testosterone supplementation and body composition: results from a meta-analysis study — Eur J Endocrinol (2016); also on PubMed. Takeaway: Across 59 trials, testosterone shifted body composition - less fat, more lean mass - even though the scale didn't move.

How this connects to care

If weight and low-T symptoms are both on your list, labs can show whether testosterone is part of the picture. See low testosterone and weight gain and sustainable weight-loss habits. TRT is $149 a month in 90-day terms ($447 per term, or $357.60 if you pay the 90 days up front). Initial labs are included; follow-up labs are billed separately. See pricing for the full list.

Relevant pages on this site:

• Tirzepatide (weight loss) (branded trial drugs are not the same as compounded products, which are not FDA-approved)
• Tirzepatide page (branded trial drugs are not the same as compounded products, which are not FDA-approved)
• TRT program

FAQ

What did this study actually find?

Dieting men on placebo lost fat AND muscle; men on testosterone lost almost only fat. The design was: Randomised double-blind placebo-controlled trial. Population: 100 obese men, T <=12 nmol/L, very-low-energy diet then maintenance, 56 weeks.

Was this a weight-loss medication study?

No. Every man followed the same very-low-energy diet; the question was what testosterone added on top of that diet in men with low-normal levels. It did not test tirzepatide or any other weight-loss medication.

What are the main limits of this evidence?

Single center, 82 completers. Intramuscular testosterone undecanoate. Obese men with low-normal T.

Keep reading

• Low Testosterone and Weight Gain: The Belly Fat Connection
• Why Consistency Matters on TRT: Skipped Doses & Results
• Benefits of Testosterone Replacement Therapy for Men

Reference

Ng Tang Fui M et al. Effects of testosterone treatment on body fat and lean mass in obese men on a hypocaloric diet: a randomised controlled trial. BMC Med. 2016. https://doi.org/10.1186/s12916-016-0700-9 · PubMed 27716209.

Next step

Book a free consult with an Arizona-licensed provider. Bring your questions — including anything this study raised for you.

TRT is $149 a month in 90-day terms, with initial labs included. See pricing for prepay and follow-up lab details.

Talk to a licensed provider. Results vary. Not medical advice.

Talk to a licensed provider. Results vary. Not medical advice.