Trulicity® (dulaglutide) and sexual function

Silence in the product information

The US label’s adverse reaction tables and text, the EU frequency table and the Canadian lists of common and less common trial events contain no entry for erectile dysfunction, reduced libido, orgasm problems or vaginal dryness. ^[1][3][4] Because the Canadian table reaches down to events reported by 1% of people, Canada adds a list of rarer ones, and the EU table runs down to rare reactions, a frequent sexual side effect would be expected to appear somewhere. ^[3][4] Absence is not proof that nothing happens, especially for symptoms people rarely volunteer in trials, but it is the first data point.

Inside REWIND: erections over five years

REWIND randomised 9,901 adults with type 2 diabetes and heart disease or several risk factors to Trulicity® 1.5 mg or placebo and followed them for a median of 5.4 years. ^[1] Men were invited to complete a standard erectile function questionnaire at the start, at 2 and 5 years and at the end. The analysis included 3,725 men with an average age of 65.5, and 2,104 of them, 56.5%, already had moderate or severe erectile dysfunction at baseline. ^[5]

New moderate or severe erectile dysfunction appeared at 21.3 per 100 person-years on dulaglutide and 22.0 on placebo, and men on dulaglutide also lost slightly less erectile function on the questionnaire score. The authors concluded that long-term dulaglutide might reduce erectile dysfunction in men with type 2 diabetes. ^[5] Three caveats matter: it was an exploratory analysis rather than a main trial goal, about 30% of the men were not included because they lacked usable questionnaires, and Eli Lilly funded the trial. The difference is small, and it says nothing about women.

Desire, hormones and sperm in healthy men

Animal research has raised the idea that GLP-1 medicines, which act on reward pathways in the brain, might dampen sexual motivation. A Swiss team tested this in people: 26 healthy, normal-weight men aged 18 to 50 with satisfying sex lives received dulaglutide and placebo for 4 weeks each, in random order and without knowing which was which. Among the 24 who finished, scores for sexual desire did not change, testosterone, FSH and LH stayed in the normal range without a meaningful difference, and sperm measures were similar. ^[6]

Four weeks is short, the men were not taking Trulicity® for diabetes, and 24 people cannot rule out a rare effect. A 2026 review of the wider field summarises the situation: rodent studies point to reduced sexual behaviour with GLP-1 activation, human findings are mixed, and there are case reports of possible sexual side effects in women that have not been studied systematically. ^[9]

What adverse event reports show

Two analyses of the FDA Adverse Event Reporting System looked at sexual problems across diabetes medicines. One found a signal for erectile dysfunction with semaglutide, sitagliptin and dapagliflozin, and no significant signal for dulaglutide, linagliptin or metformin; the authors called their findings preliminary. ^[7] The other pooled male sexual problems across six GLP-1 medicines, including dulaglutide, and found 182 cases with reporting lower than expected overall, concluding that the association was weak. ^[8]

These databases depend on who chooses to report. They cannot count how many people take a medicine, they cannot separate the drug from the diabetes it treats, and they cannot show cause and effect.

How Trulicity® could plausibly matter

• What the labels support: nothing directly. The US label reports no effect on fertility or mating in rat studies, the EU summary states that the effect on human fertility is unknown, and Canada describes hormone changes in young male and female rats, and earlier puberty in the females, only at about 38 times the highest human exposure, which it does not consider relevant at prescribed doses. ^[1][3][4]
• Proposed but not proven: brain reward circuits that respond to GLP-1 also influence sexual motivation in animals, which is why researchers tested desire in the trial above. ^[6][9]
• Indirect routes with some support: NIDDK explains that high blood glucose damages nerves and blood vessels needed for sexual function, and that both high and low blood glucose can interfere with arousal. ^[12] Better glucose control is the pathway the REWIND authors considered when they compared erectile results with other diabetes outcomes. ^[5]

Common causes beyond the medicine

MedlinePlus explains that most erection problems have a physical cause, such as narrowed arteries, nerve disorders, low testosterone, heart medicines like digoxin, prostate surgery, nicotine, alcohol or drug use, while stress, anxiety and relationship strain also play a part. ^[10] For women, MedlinePlus lists diabetes, heart disease, nerve disorders, hormone problems, some medicines, stress, depression and relationship concerns. ^[11]

Diabetes itself is a major factor. NIDDK says men with diabetes may develop erectile dysfunction 10 to 15 years earlier than men without it, and that women with diabetes can have low desire, vaginal dryness and painful sex from nerve damage, reduced blood flow and hormonal changes; yeast infections are also more frequent. ^[12] Feeling unwell during the early weeks of treatment, nausea or tiredness can lower interest in sex too, and a low mood is worth mentioning separately.

What the sources suggest

MedlinePlus lists regular exercise, a healthy diet, weight loss if needed, good sleep, not smoking, limiting alcohol, avoiding illegal drugs and keeping blood sugar well controlled as ways to prevent or improve erection problems, and suggests counselling when communication with a partner is hard. It cautions that herbs and supplements sold for sexual performance are unproven and may be unsafe, and asks you not to stop or change any medicine without talking to your provider first. ^[10]

NIDDK suggests working with your healthcare team on blood glucose, blood pressure and cholesterol, getting help for emotional difficulties, and, if you use insulin, checking blood glucose before and after sex because both highs and lows can cause problems. ^[12] People taking Trulicity® with insulin or a sulfonylurea have a higher risk of low blood sugar, so that check is especially relevant. ^[1][2] If you are thinking about pregnancy, the EU leaflet advises contraception during treatment and asks you to tell your doctor if you plan to have a baby. ^[3]

Trulicity® is a registered trademark of Eli Lilly and Company. PepLabo is not affiliated with or endorsed by Eli Lilly and Company.