Is there a risk that this will turn us back into babies?
No, this risk is completely ruled out. Here it is important to understand the difference between aging and development.
Development is a program that is encoded in our genes, begins at conception and ends in adulthood. It turns us from an egg cell into an adult human being and takes us through all the intermediate steps required for this. The self-maintenance of our body (i.e. the repair mechanisms within us that already repair aging damage) is also a program encoded in our genes, which begins at conception and never ends, but which works less and less well because of aging. Aging is not a program, but the result of gaps in the self-maintenance program 1.
Rejuvenation therapies can and should only remove the molecular and cellular damage that arises as a side effect of normal metabolic processes and "slips past" the self-maintenance program. They do not affect the developmental process. If we define biological age as the amount of damage in the body, an adult - provided the therapies are thorough enough - could therefore have the biological age of a 10-year-old or an even younger person and would still be just as grown-up as ever.
- Kirkwood TB. Time of our lives. What controls the length of life? EMBO Rep 2005 Jul; 6 Spec No (Suppl 1): S4-8. doi: 10.1038/sj.embor.7400419. PMID: 15995661; PMCID: PMC1369269.