The short version
Recent meta-analyses find real benefits from health coaching in quality of life, self-efficacy, disability, pain, and HbA1c. Most effects are small.
Certainty is low or very low for most outcomes, because trials differ widely, define coaching differently, and rarely follow people past a year.
Reviews don't always agree. Depression improved in a chronic illness review and did not in a review of older adults.
The honest pitch is "a promising, low-risk support for behavior change," not "proven to work."
What the meta-analyses find
Boehmer et al. (2023) pooled 30 randomized trials of health and wellness coaching in people with chronic conditions. Coaching improved quality of life at 3 months, self-efficacy at 1.5 months, and depressive symptoms at 3, 6, and 12 months. Anxiety did not change at any point, and the quality of life benefit was gone by 6 months. The authors rated certainty low or very low for most outcomes.
Reviews of single conditions tell a similar story. Across 26 trials in adults with chronic non-cancer pain (4,403 people), Barnet-Hepples et al. (2024) found a trivial-to-small effect on physical activity and small effects on disability and pain; the effect on quality of life was unclear. Across 20 trials in type 2 diabetes (3,222 people), Almulhim et al. (2023) found a small effect on HbA1c (g = 0.29), with 8 trials reaching a clinically meaningful drop.
A newer review in older adults (Yang et al., 2026; 35 trials, 20,200 people) found small gains in quality of life and self-efficacy and a very small drop in anxiety, but no significant effect on depression. Certainty ranged from very low to moderate.
A quick guide to the numbers: a standardized effect (SMD or g) of about 0.2 is conventionally small, 0.5 moderate, and 0.8 large. Most pooled coaching effects fall between about 0.2 and 0.4. The few moderate estimates, such as Boehmer's 3-month quality of life result, come with wide confidence intervals.
The compendia many coaches cite are a different kind of source. Sforzo et al. (2018) catalogued 219 coaching articles and called coaching "a promising intervention for chronic diseases though further research is needed in most categories." The 2020 addendum added 104 articles. These are useful maps of the literature, but they collect studies rather than pool them, include designs other than randomized trials, and some authors disclosed ties to a coach training company. Treat them as a reading list, not a verdict.
Why certainty stays low
Heterogeneity. Trials differ in who was coached, how many sessions, phone or in person, and what the comparison group got. In Boehmer's quality of life analysis, 86% of the variation between studies came from real differences rather than chance (I² = 86.3%).
"Coaching" means different things. Coaches in Boehmer's trials included nurses, therapists, health psychologists, and peer coaches. Almulhim et al. named "inadequate, imprecise descriptions of interventions and the lack of theory" as the main limits, and no single behavior change technique stood out. In hypertension, Meng et al. (2023) found larger blood pressure effects when nurses delivered the coaching. A trial result is rarely a direct test of a board-certified coach working on their own.
Short follow-up. Boehmer found no long-term benefit but noted that few studies looked past a year. A rapid review by Ahmann et al. (2024) found 25 of 28 studies showed at least partly sustained gains on 1 or more outcomes. That is a count of studies, not a pooled effect, so read it as an encouraging signal.
No blinding. Sforzo et al. (2018) note that blinding participants and coaches is impractical, and the outcomes in Boehmer's review were all self-reported scales. Both leave room for bias.
Using it with clients, employers, and clinical partners
With an employer or clinic, lead with what the evidence supports, give the size, and name the limits in the same breath. For example: "In chronic condition trials, coaching has improved quality of life, confidence in self-management, and depressive symptoms in the short term. The effects are mostly small and the evidence is still low certainty, so I'd suggest we agree on a few outcomes and track them together." Then follow through: choose 2 or 3 outcomes in advance and measure them at the start and at set points afterward. Your own data will mean more to that partner than any pooled estimate.
Skip "proven," "reverses," and promises about lab values. The HbA1c changes in trials happened alongside medical care, and interpreting a client's labs is outside a coach's scope (National Board for Health & Wellness Coaching [NBHWC], n.d.).
With clients, the evidence can set realistic expectations without dampening hope. Start with what they want coaching to change:
"What would tell you, a few months from now, that this was worth your time?"
"Would it be helpful if I shared what the research says about what coaching tends to help with?"
"You want this to be the thing that finally sticks, and you also want to know it's realistic."
"Studies have found coaching can help people feel more confident managing their health. How does that fit with what you're hoping for?"
Small average effects still leave room for meaningful change in one person. The client's own progress toward their own goals is the most relevant evidence in the room.
Where coaching stops
The NBHWC Scope of Practice says coaches do not diagnose, interpret medical data, prescribe or de-prescribe, or provide psychological therapeutic interventions or treatment. When working under the license of a qualified medical or allied health professional, coaches may support that professional's treatment plan (NBHWC, n.d.). So don't market coaching as treatment for depression, diabetes, or chronic pain, even though trials measured those outcomes. Refer worsening mood to a mental health professional, and lab, medication, or symptom questions to the client's physician.
Go deeper
The Evidence Literacy for Coaches package, which covers effect sizes, certainty ratings, and conflicts of interest, is in development, as is The Clinical Health Coach package on working with clinical teams and describing outcomes.
References
Ahmann, E., Saviet, M., Conboy, L., Smith, K., Iachini, B., & DeMartin, R. (2024). Health and wellness coaching and sustained gains: A rapid systematic review. American Journal of Lifestyle Medicine, 18(2), 162–180. https://doi.org/10.1177/15598276231180117
Almulhim, A. N., Hartley, H., Norman, P., Caton, S. J., Doğru, O. C., & Goyder, E. (2023). Behavioural change techniques in health coaching-based interventions for type 2 diabetes: A systematic review and meta-analysis. BMC Public Health, 23(1), 95. https://doi.org/10.1186/s12889-022-14874-3
Barnet-Hepples, T., Dario, A., Oliveira, J., Maher, C., Tiedemann, A., & Amorim, A. (2024). Health coaching improves physical activity, disability and pain in adults with chronic non-cancer pain: A systematic review. Journal of Physiotherapy, 70(2), 115–123. https://doi.org/10.1016/j.jphys.2024.01.001
Boehmer, K. R., Álvarez-Villalobos, N. A., Barakat, S., de Leon-Gutierrez, H., Ruiz-Hernandez, F. G., Elizondo-Omaña, G. G., Vaquera-Alfaro, H., Ahn, S., Spencer-Bonilla, G., Gionfriddo, M. R., Millan-Alanis, J. M., Abdelrahim, M., Prokop, L. J., Murad, M. H., & Wang, Z. (2023). The impact of health and wellness coaching on patient-important outcomes in chronic illness care: A systematic review and meta-analysis. Patient Education and Counseling, 117, 107975. https://doi.org/10.1016/j.pec.2023.107975
Meng, F., Jiang, Y., Yu, P., Song, Y., Zhou, L., Xu, Y., & Zhou, Y. (2023). Effect of health coaching on blood pressure control and behavioral modification among patients with hypertension: A systematic review and meta-analysis of randomized controlled trials. International Journal of Nursing Studies, 138, 104406. https://doi.org/10.1016/j.ijnurstu.2022.104406
National Board for Health & Wellness Coaching. (n.d.). Scope of practice. Retrieved November 1, 2026, from https://nbhwc.org/wp-content/uploads/2026/08/Scope-of-Practice-PDF.pdf
Sforzo, G. A., Kaye, M. P., Harenberg, S., Costello, K., Cobus-Kuo, L., Rauff, E., Edman, J. S., Frates, E., & Moore, M. (2020). Compendium of health and wellness coaching: 2019 addendum. American Journal of Lifestyle Medicine, 14(2), 155–168. https://doi.org/10.1177/1559827619850489
Sforzo, G. A., Kaye, M. P., Todorova, I., Harenberg, S., Costello, K., Cobus-Kuo, L., Faber, A., Frates, E., & Moore, M. (2018). Compendium of the health and wellness coaching literature. American Journal of Lifestyle Medicine, 12(6), 436–447. https://doi.org/10.1177/1559827617708562
Yang, Y., Yu, L., Chen, Y., & Wang, Z. (2026). Effectiveness of health coaching interventions on anxiety, depression, self-management behaviors, self-efficacy, and quality of life among older adults: A systematic review and meta-analysis of randomized controlled trials. Worldviews on Evidence-Based Nursing, 23(1), e70108. https://doi.org/10.1111/wvn.70108
