"alone insufficient" is correct and can be used in written English
You can use it to highlight that something does not provide enough of a result in and of itself. For example, "The single hour of practice was alone insufficient to improve her skill level."
Field measurements from Tlaxcala, Mexico stress that restoring agricultural structures (the arrangements of landforms and vegetation) is alone insufficient.
Likewise, financial incentives - the knee-jerk solution offered as a panacea by countless commentators and policymakers in the last seven years -- are alone insufficient to trigger improvement, just as offering that same beginner millions of dollars to play that concerto will do little to guarantee a better performance.
Moreover, as FG-repeat proteins often carry no other distinguishing features, we deemed the presence of FG-repeats alone insufficient for assigning membership to the NPC, and such candidates were excluded from our study (Table 1).
This is consistent with the widespread inactivation of CDKN1C in many different cancers with additional oncogenic mutations and suggests that CDKN1C silencing contributes, but is alone insufficient, to cause tumors.
The mechanism highlighted by our data is that besides its strong influence on CaO2, rhEpo was found to enhance leg V̇O2max in normoxia through a preferential redistribution of cardiac output toward the exercising legs, whereas this advantageous effect disappeared during severe hypoxia, leaving augmented CaO2 alone insufficient for improving peak leg O2 delivery and V̇O2.
Appropriate chemical stimuli (prey extracts) are alone insufficient to trigger discharge of nematocysts.
