The honest summary
For the foundational practices that tantra shares with mindfulness and contemplative meditation, the research base is substantial and high-quality. For the specific tantric protocols (Daoist sexual practice, partnered tantric exercises, breath-orgasm protocols), the research is sparse and mostly small-sample. For the energetic-body claims (chakras, kundalini, microcosmic orbit as literal energy circulation), there is essentially no rigorous research and the existing studies have serious methodological limitations.
Strong evidence — breath and attention practices
Sustained breath practice and attention training (the foundational layer of tantric practice) have a substantial published evidence base. Effects on cortisol, heart rate variability, parasympathetic tone, and self-reported anxiety are well documented in clinical trials. The mindfulness research (Kabat-Zinn lineage) generalises directly to the foundational tantric breath/attention work.
Strong evidence — sensate focus and behavioral sex therapy
The specific behavioral protocols that contemporary tantric practice draws from — sensate focus, the start-stop technique, pelvic-floor training — have decades of research behind them. Masters and Johnson published the original sensate focus research in the 1970s; the protocol remains the most-prescribed couples sex-therapy intervention today.
Moderate evidence — mindfulness-based interventions for sexual issues
Lori Brotto's research at UBC has shown solid effects of mindfulness-based interventions on female sexual desire and arousal. The interventions are essentially tantric-foundational practice in clinical clothes — slow breath, body-attention, present-moment awareness applied to sexual experience. The evidence here is meaningful.
Limited evidence — Daoist sexual practice
The Daoist sexual practices (microcosmic orbit, big draw, non-ejaculatory orgasm) have a long classical literature but limited modern empirical research. Some small studies on mindfulness-based interventions for premature ejaculation show meaningful effects. The trained capacity for non-ejaculatory orgasm is documented in case series but has not been studied in large trials.
Limited evidence — partnered tantric practice
A small number of studies on tantric workshops and programs report self-improvement in relational and sexual measures. Sample sizes are small and study quality is mixed. The aggregate signal is positive but the evidence base is not yet robust.
Essentially no evidence — chakra/kundalini claims as literal energetics
The classical tantric vocabulary describes a "subtle body" with specific energy centres and channels. As phenomenology — what people consistently report experiencing — there is rich descriptive consistency across cultures and centuries. As literal physical anatomy — there is no research support and the framework is not falsifiable in the standard scientific sense. Modern teachers handle this differently; we treat the energetic vocabulary as useful phenomenological description rather than literal anatomy.
What this means practically
For the foundational tantric practices — breath, attention, body-mapping, sensate focus, behavioral sex protocols — you can confidently expect meaningful effects on the issues most people work on. For the more advanced practices — partnered tantric work, Daoist sexual cultivation — the evidence is weaker but the practitioner reports are consistent. For the metaphysical claims — hold them lightly, treat them as phenomenology, do not stake your worldview on them.