Background/introduction Risky sexual behaviours remain the drivers behind new HIV infections within MSM in the UK. Understanding reasons behind risk behaviour could inform HIV prevention strategies.

Aim(s)/objectives To document sexual appetite/libido among MSM taking PEPSE, and to examine the relations between libido and risk behaviours.

Methods Data were collected at enrolment, as part of an ongoing RCT evaluating a behavioural intervention to reduce HIV risk behaviour. Within this study, a 10-item measure of libido was included (possible range of scores 10–40). This assessed how much thoughts and feelings about sex were considered disruptive.

Results 171 MSM responded (mean age 34.5, SD 9.1, range 19–66 yrs). Mean (SD) libido score was 20.4 (7.7); median was 19 (range 30). Those with higher libido reported a higher number of sexual partners, both insertive (r_s = 0.298; p ≤ 0.001; n = 162) and receptive (r_s = 0.329; p ≤ 0.001; n = 164), and inconsistent condom use, both insertive (r_s = 0.185;p = 0.042; n = 121) and receptive (r_s = 0.227; p = 0.009; n = 132). Higher libido was associated with higher levels of loneliness (r_s = 0.401; p ≤ 0.001; n = 165); reduced self-efficacy (r_s = −0.230; p = 0.003; n = 165), action planning (r_s = −0.182; p = 0.019; n = 164), intentions (r_s = −0.163; p = 0.036; n = 165) and behavioural likelihood (r_s = −0.228; p = 0.003; n = 165) of performing safer sex strategies. Loneliness was related to inconsistent condom use, both insertive (r_s = 0.191; p = 0.021; n = 147) and receptive (r_s = 0.165; p = 0.036; n = 162), and a high number of sexual partners (receptive) (r_s = 0.164; p = 0.033; n = 171).

Discussion/conclusion Risky behaviours are related to stronger sexual appetites/libido and loneliness within this sample. The potential importance of libido and loneliness should be recognised within the context of future HIV prevention efforts.